Chlorine measurement/filter testing/brine container monitoring of a water treatment system

ABSTRACT

The water treatment system, particularly reverse-osmosis system, comprising a water line with a plurality of filter stages, is characterized in that before and after at least one filter stage a respective line branches off from the water line, which is provided with a valve adapted to be switched by a control device and leads to a pressure sensor device.

FIELD OF THE INVENTION

The present invention refers to a fluid system for quality/functionmonitoring and/or control of physically and chemically acting filterstages of a water pretreatment for the operation of a reverse-osmosis oranother water treatment or water monitoring system.

BACKGROUND OF THE INVENTION

Filter routes have the disadvantage that the remote diagnosis ofchlorine and hardness or the monitoring of the degree of soiling ofmechanical filters, respectively, cannot be carried out or can only becarried out by taking great efforts.

Moreover, it is necessary for reasons of safety, particularly indialysis water treatments, that a time-consuming manual documentation ofthe water hardness and/or of the chlorine content should be carried outdaily, especially in order to furnish evidence that the toxic chlorinehas been removed from the liquid by the filters used.

Existing chlorine sensors for online measurement are often notchlorinated at regular intervals and cannot provide any reliablemeasurement results in the absence of chlorine in the liquid.

To remove hardly soluble salts, such as calcium and/or magnesium, fromthe water, softeners are often used. When softeners are used with acidiccation exchange resins, these must be regenerated by means of sodiumchloride brine solution at regular intervals.

This regeneration is normally carried out with sodium chloride solutionwhich is provided in a so-called brine container in which salt isdissolved in a predetermined liquid amount. Failure of the regenerationprocess e.g. because of a missing sodium chlorine brine solution maylead to serious calcification of the downstream systems.

Moreover, softeners tend to show a microbial growth with subsequentcontamination of the liquid flowing therethrough because of therelatively large resin volume.

Problems are posed by filter blocking because the resulting exchange offilter material is normally accompanied by operational interruption.

SUMMARY OF THE INVENTION

It is the aim of the invention to permit the development of anactuator-sensor control and software which enable the user to evaluatethe functionality of a system by online access and to obtain, on thisbasis, a remote diagnosis about the current operational state.

To meet the normative and/or in-house requirements, the necessarydocumentation evidence can be furnished simultaneously together with theautomatic recording by way of the connected electronic data processingsystem.

It is possible on account of the desired system-specific evaluation byanalysis and visualization of the operational parameters to achieve anacyclic distribution of the service operations and thus a reduction ofthe number of services.

On this basis an economic and ecological procedure is possible as thedeployment of trained stuff on site can thereby be coordinated in animproved way and failure caused by wear can be avoided in a targeted andpreventive way.

To avoid the aforementioned drawbacks and to comply with the objective,respectively, partial streams are passed under one aspect of the presentinvention to the corresponding sensor before and after the filter stagesby means of switched valves and are evaluated by electronic measuringdevices. These measuring devices may here also be an integral part ofsubsequent systems of a water treatment and/or also a control room. Abidirectional operation for influencing actuators and sensors is herealso possible.

Advantageously, with an electronic pressure sensor different mechanicalfilter stages are monitored online with respect to their degree ofsoiling by measuring the pressures and determining the pressuredifference and an automatic backwashing program is also started in thecase of suitable filters with a corresponding automatic backwashingsystem.

Under another aspect of the invention, use is made of an onlinemeasuring chlorine sensor the safety-relevant function of which ischecked according to the invention by supplying electrolyticallyproduced chlorine of a known concentration to the sensor at regularintervals. The measurement result is electronically recorded anddocumented. The chlorine can be produced from an existing brinesolution.

The function of the softener, i.e. the filtration and reduction of thehardly soluble calcium and magnesium salts, can be monitored by anion-sensitive calcium and/or magnesium sensor.

The fill level of the salt water container and the residual volume ofthe salts in the brine container, respectively, have to be monitored ina simple way by means of a weighing device. To this end the brinecontainer is placed on a constructional element with weighing cell.Since the constructional understructure can advantageously be used atany time independently of the brine container used, brine containersthat are already in use can also be equipped with the monitoring device.It is possible to indicate the brine volume directly or as asignal-light solution with message color; transfer to and recording in acontrol room or a subsequent water treatment system, which may e.g. beconfigured as an RO system, is also possible. Inspection anddocumentation of the salt supply in the brine container which has to becarried out by the operating personnel daily can thus be dispensed with.

A regular slight chlorination of the softener during regeneration bychlorine which is electrolytically produced from the brine container ofthe softener reduces the microbial growth in the softener resin andthereby ensures a more sterile liquid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows is a schematic diagram of a pre-filtration unit accordingto the invention.

FIG. 2a is a cross-sectional view of a salt water container according tothe invention.

FIG. 2b is a top perspective view of a weighing platform according tothe invention.

FIG. 2c is a bottom perspective view of the weighing platform of FIG. 2b.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a pre-filtration unit according to the invention with amechanical-chemical filter stage (4), an actuator-sensor monitoring unit(3), an associated electronic evaluation unit (2), and a possibleelectronic unit (5) pertaining e.g. to a downstream reverse osmosissystem, wherein the electronic unit (2) may also be configured as acontrol-room electronic and may communicate with the electronic unit(5).

The mechanical-chemical filter stage (4) is only shown by way of examplewith respect to the selection of the arranged filter stages so to as toillustrate the function of the monitoring operation according to theinvention.

The exemplary arrangement begins with the water inlet (6), a shut-offvalve (8), and an automatically back-washable pre-filter (9) with drainvalve and drainage connection. This is followed by a safety shut-offvalve (10) which is activated by a leakage indicator (22 a) with liquidsensor (22 b).

Further components may be a pipe separator (11) and a backflow preventer(12) for avoiding contamination of the water inlet (6).

At low water supply pressures it is possible to add a pressureincreasing unit (13). A further filter stage (14) may be configured as acartridge filter (14 a), sand filter (14 b) or also as a hollow fiberfilter (here not shown) in the nano or ultra-pore range.

(15) shows a softener, e.g. illustrated as a twin softener, which isnormally filled with strongly acidic, cation-containing resin which uponexhaustion has to be regularly regenerated with NaCl solution from thesalt water treatment (16). It is here important to monitor the filllevel of the salt in the salt water container (16). This is done with aweighing device (17), which is designed as an independent constructionalunderstructure.

According to FIG. 2 the weighing device (17) consists of a weighing cell(46) the signal of which can be amplified by electronics (44) on theweighing platform (42), electronically processed, or can be processed byelectronics (2) and also by possibly successive electronics (5). Presetweight limit values of the brine container can here be monitored andoptically or acoustically indicated or remotely diagnosed by technicalelectronic data processing. The weighing cell (46) is fastened to theweighing platform (42) by means of screws (48) such that a third of thebrine or salt weight weighs on the measuring foot (47). Side boundaries(45) are mounted for the lateral guidance of the brine container.

During the regeneration process of the softener (15) chlorine-containingsolution can be formed with the help of the electrolysis device (18)from the salt water flowing towards the electrolysis cell. It goeswithout saying that the chlorine concentration depends on the brineconcentration, but substantially on the magnitude of the electricallysupplied power to the electrolysis cell. The microbial growth in thesoftener resin is thereby strongly reduced.

(19) shows a twin carbon filter/dechlorination device which is used forthe filtration of the chlorine.

Filter stage (20) as a fine-filter stage can remove the smallestparticles from the filter water (7) before it is e.g. supplied to areverse osmosis system or a drinking water installation.

The actuator-sensor unit (3) can be equipped with an electronic watermeter (21) for recording and reporting the water consumption.

For monitoring the chlorine content of the supplied liquid a chlorinesensor (30) is preferably positioned in a chlorine sensor chamber (29),either for the measurement of the whole chlorine or of the freechlorine.

The chlorine sensor chamber (29) has an inlet and a free outlet. Therelease valve (28) is directly positioned in front of the sensorchamber. Usually, the supplied liquid can be chlorinated by the watersupplier with chlorine of different concentrations; depending on thehygienic state, a chlorine input may be temporarily missing. In such acase no statement can thus be made on the proper function of the sensor(30).

For regularly checking the chlorine sensor the test valve (27), thebrine suction valve (24), and the release valve (28) are opened and theelectrolysis cell (18) is switched on. The brine or thechlorine-containing solution is sucked in a selected concentration ratiofrom the container (16) via the adjustable brine suction valve (24) andthe pump (23), mixed with liquid via flow throttle (25), passed on tothe measuring chamber (29), recorded via chlorine sensor (30) andevaluated with electronics (2) and (5), respectively.

The proper function of the measuring cell (30) is ensured by thisregular testing. It is within the meaning of the present invention toprovide and monitor the sodium chloride brine solution also exclusivelyfor the purpose of chlorine sensor monitoring, independently of asoftener or other filter stages. The suction line of the brine solutionand the electrolysis cell for the electrolytic chlorine production arehere independent of the brine suction line and the electrolysis cell ofthe softener.

Pump (23) is shown by way of example as a venturi pump; other pump typesare possible for performing the function; in such a case thechlorine-containing solution is supplied in metered amounts by means ofa pump (not shown) from line 24 a into line 25 a.

For monitoring the correct carbon filter function/dechlorination device(19) a valve, e.g. (40) or (27), may first be opened. Likewise, releasevalve (28) is opened. If chlorine is contained in the supplied liquid,this is recorded via the previously verified chlorine sensor (30).

Thereupon, the valves (33, (31) or also (32) are successively opened;likewise, the chlorine release valve (28) is opened. For instance, thefilter stages of the carbon filter can be tested. If the chlorine sensorrecords the absence of chlorine, the checking of the filter issuccessfully completed. It is within the meaning of the presentinvention that this measurement can also be carried out independentlyand recorded technically by electronic data processing.

For monitoring the filter stages (9), (14), (30) the pressure sensor(41) is acted upon selectively and successively before or after thefilter stages with the pressures prevailing at the filter stages via thevalves arranged in FIG. 1.

For instance, the pressure drop of the filter stage (9) is monitored bymeasuring the inlet pressure via valve (37) and the outlet pressure ismonitored by the valve (38).

As an equivalent to the said measurement, FIG. 1 shows the measurementof the pressure drops by switching the valves (39/40) for the filterstage (14) and the valves (31/32) for filter stage (20).

A determination of the pressure drops at softening stage (15) anddechlorination stage (19) is also possible by way of a successiveswitching of the valves (40, 27, 33, 31).

An atmospheric relief of the pressure sensor (41) in general or between2 measurements can be carried out via valve (34) and also (28).

By measurement of the flow through line 6 with water meter/flow meter(21) or also by a corresponding flow measurement in a subsequenttreatment process, the pressure values measured on the filters can becalculated by means of electronics (2, 5) as standard or mean values anda warning, exchange, flushing or maintenance time can be predicted forpreset pressure differences.

Since the determination of the filter pressure differences normallyregards relative measurements, the use of a single pressure sensor (41)is advantageous both in terms of costs and in terms of the calibrationefforts.

As a rule, the water inlet pressures on line (6), e.g. on filter (9),are known, so that the pressure sensor (41), acted upon with a knownpressure before the beginning of a measurement cycle, must be verifiedduring maintenance or during inspection by a technician.

An advantageous development of the pressure measurement is thedetermination of mean pressure values by means of electronics (2, 5) onthe respective filters (9, 14, 15, 19, 20) in that e.g. 50 measurementsare combined to form a mean value and are represented over an exemplaryperiod of 1000 operating hours. Changes that are due to the service lifeend of the sensor (41) or the blocking of the aforementioned filters canbe recognized technically by electronic data processing or predicted,respectively, and remotely inquired.

To monitor the correct function of the softener (15), valve (40) isfirst of all opened and hard water is supplied over measuring chamber(35) to the calcium sensor (35) through the opened valve (34).Subsequently, softened liquid is passed via flow throttle (25), valves(27, 34) into the measuring chamber (35) to the ion-sensitive calciumsensor (36).

Legend 1. Pre-filtration with sensor package 2. Electronics sensorpackage 3. Actuator and sensor unit 4. Pre-filtration components 5.Electronics post-filtration 6. Water inlet 7. Filter water 8. Shut-offvalve 9. Back-flushable pre-filter with cleaning valve 10. Safetyshut-off valve 11. Pipe separator 12. Backflow preventer 13. Pressureincreasing unit 14. Fine-filter stage 2 15. Softening stage 16. Saltwater treatment/brine tank 17. Weighing unit 18. Electrolysis cell 19.Dechlorination stage/carbon filter 20. Fine-filter stage 3 21. Watermeter/flow meter 22. Leakage indicator with sensor 23. Brine pump 24.Brine suction valve 25. Flow throttle 26. Backflow preventer 27.Chlorine sensor test valve/calcium check valve I 28. Chlorine sensorrelease valve 29. Chlorine sensor chamber 30. Chlorine sensor 31.Chlorine check valve II/fine-filter stage 3 inlet pressure 32. Chlorinecheck valve III/fine-filter stage 3 outlet pressure 33. Chlorine checkvalve I 34. Calcium sensor release valve 35. Calcium sensor chamber 36.Calcium sensor 37. Fine filter stage 1 inlet pressure 38. Fine filterstage 1 outlet pressure 39. Fine filter stage 2 inlet pressure 40. Finefilter stage 2 outlet pressure/calcium test valve 41. Pressure sensor 6a Lines  6b 16a 19a 24a 25a 42. Platform 43. Adjustable feet 44.Electronics 45. Side boundary 46. Weighing cell 47. Measurement foot 48.Mounting of weighing cell

The invention claimed is:
 1. A water treatment system, particularlyreverse-osmosis system, comprising a water line with a plurality offilter stages, wherein before and after each of the filter stages arespective branch line branches off from the water line, each of thebranch lines leads to a joint pressure sensor that is connected to anelectronic evaluator to determine the respective pressure differences ofall filter stages, wherein a valve adapted to be switched by a controldevice is provided in each said branch line in between the branch offfrom the water line and the pressure sensor, and wherein at least onerelief valve connects the pressure sensor to the atmosphere, and whereinthe electronic evaluator is configured to atmospherically relieve thepressure sensor between at least two pressure measurements via therelief valve.
 2. The water treatment system according to claim 1 whereinan automatic backwashing system and an automatic backwashing program areprovided for each filter stage.
 3. The water treatment system accordingto claim 1 wherein the plurality of filter stages includes aback-flushable pre-filter with cleaning valve, a fine filter and anultrafine filter.
 4. A method for the function monitoring of a pluralityof filter stages of a water treatment system, particularly areverse-osmosis system, comprising measuring a respective pressure dropfor each filter stage with a joint pressure sensor, electronicallyevaluating pressure measurement values from the joint pressure sensor,and atmospherically relieving the joint pressure sensor between at leasttwo pressure measurements via a relief valve.
 5. The method according toclaim 4 wherein an automatic backwashing program is started when apredetermined pressure difference is reached.
 6. The method according toclaim 4 wherein measurement results are recorded and documentedelectronically.
 7. The method according to claim 4 wherein mean pressurevalues for each filter stage are electronically determined from multiplepressure measurements.